function limit(str, maxBytes) {
  if (lenB(str) <= maxBytes) {
    return len(str);
  }
  for (i = int(maxBytes / 2) + 1; i <= maxBytes; i++) {
    if (lenB(left(str, i)) > maxBytes) {
      return (i - 1);
    }
  }
  return maxBytes;
}

[3,1] = "�Z��3";

for (y = 2; y <= Bottom; y++) {
  address = str([1,y]) + str([2,y]);
  p = limit(address, 30);
  [1,y] = left(address, p);

  address = mid(address, p + 1);
  p = limit(address, 30);
  [2,y] = left(address, p);

  [3,y] = mid(address, p + 1);
}